The Richmond, Va., Police Department will no longer dispatch patrol units to investigate some assault cases, in an expansion of the practice that is aimed at freeing up officers from having to respond to unnecessary, time-consuming calls.

Under the policy, which is known as “differential police response,” officers will not respond to assault incidents where no medical attention is required or if the suspect is no longer at the scene. Residents are being urged to call the department so that reports about those offenses can be taken over the telephone.

The policy does not apply to domestic assault incidents, said police spokesman Capt. Arthur Roane, who said the 700-officer department has a “preferred arrest” policy in domestic cases.